About 30 years after it was discovered to be missing — and 500 years after it was written — the F.B.I. has returned a document bearing the signature of the Spanish conquistador Hernán Cortés to Mexico.

The manuscript, a register of payments from 1527, is one of 15 pages believed to have been stolen from Mexico’s national archives between 1985 and 1993, the F.B.I. said. It was signed by Cortés, who led the overthrow of the Aztec empire for the Spanish crown.

The F.B.I. said that it returned the document on Wednesday, and that no one would face prosecution in the theft because the document had changed hands many times since it vanished.

The document “outlines the payment of pesos of common gold for expenses in preparation for discovery of the spice lands,” Special Agent Jessica Dittmer, a member of the F.B.I.’s Art Crime Team, said in a statement, “so it really gives a lot of flavor as to the planning and preparation for unchartered territory back then.”

Those “spice lands” that Ms. Dittmer spoke of were eastern and southeastern Asia. European explorers sailed west in the hopes of finding a faster route to the region, and instead landed in the Americas.

In 1993, while archivists at the General Archive of the Nation in Mexico were creating microfilms of their collection of documents signed by Cortés, they discovered that 15 pages of the manuscript were missing.

The archive used a distinctive wax numbering system from 1985 to 1986, which helped F.B.I. investigators to authenticate the stolen page, the F.B.I. said. The archivists had noted which numbered pages had been stolen and had recorded the precise rip pattern in the torn pages.

“This 1527 manuscript, signed by Hernán Cortés, captures a pivotal moment when the Pacific routes were opening and New Spain sought to connect the Americas with Asia,” a spokesperson from Mexico’s Embassy in Washington said in a statement on Thursday.

“Linked to an expedition to the Spice Islands (Maluku Islands, in present-day Indonesia), it is part of the legacy of the Hospital de Jesús, founded by Cortés.” Cortés founded the hospital in 1524.

Investigators said they believed that the archivists’ careful accounting would help them find the pages that were still missing.

They said that they had added this missing page to the National Stolen Art File, an F.B.I. database of artworks and cultural artifacts known to be stolen.

Though they did not detail their investigative process, they said that open-source research had revealed that the document was in the United States, though they did not say who had it.

Last year, Mexico asked that the Art Crime Team help to search for this particular page, the F.B.I. said. The New York City Police Department, the Justice Department, the Mexican government and the F.B.I.’s office in Atlanta took part in the investigation, officials said.

The document, dated Feb. 20, 1527, contains a full accounting of the logistical details related to Cortés’s journey to what would eventually become the territory of New Spain, which included present-day Mexico and parts of the United States, Central America and the Caribbean, Ms. Dittmer said.

New Spain, a colonial territory of the Spanish Empire, was founded in the early 16th century and existed until Mexico declared its independence in 1821.

“Pieces like this are considered protected cultural property and represent valuable moments in Mexico’s history, so this is something that the Mexicans have in their archives for the purpose of understanding history better,” Ms. Dittmer said in a statement.

Cortés reached the shores of present-day Mexico in 1519, aiming to overthrow the Aztec emperor Montezuma in the Aztec capital of Tenochtitlan, which is now Mexico City.

The Aztecs initially beat back the Spanish invasion, but Cortés made alliances with local groups that opposed the Aztecs and returned in 1521.

His second siege was successful, and he took over the city after burning it to ruins. The Spanish ruler, Charles V, named Cortés the governor of New Spain in 1522.

Cortés and the Spanish settlers brought with them diseases like smallpox, which ripped through the native population. Within five years, disease had killed as many as 15 million Aztecs.

“The United States — for better or for worse — is one of the largest, if not the largest, consumer of art and antiquities,” said Veh Bezdikian, a supervisory special agent with the F.B.I. in New York.

This is the second Cortés document that the F.B.I. has returned to Mexico in recent years. In 2022, the F.B.I. discovered another page of the purchase order signed by Cortés that had made its way to private auction blocks across the United States.

The Art Crime Team is still looking for other missing pages from Mexico’s national archives.